The present invention relates to single chip or multiple chip light emitting diodes (LEDs) or ultraviolet radiating illuminator, and more particularly to single or multiple chip ultraviolet light emitting diodes that operate under standard alternating current (AC) high voltage conditions for various applications including water purification, air purification, germicidal lamps, ultraviolet curing, etc.
Group III nitride LED systems have proven to be efficient, compact and robust solid-state UV optical sources and sensors. This has stimulated the development of ultraviolet optical devices. Rapid progress in material growth, device fabrication and packaging enabled demonstration of high efficiency visible-blind and solar-blind photodetectors, deep-UV light emitting diodes (UVLED) with emission from 250 to 400 nm, and UV laser diodes with operation wavelengths ranging from 340 to 350 nm. Applications of these UV optical devices include flame sensing; fluorescence-based biochemical sensing; covert communications; air, water, and food purification and disinfection; and biomedical instrumentation.
Currently, semiconductor LEDs are energized by direct current (DC) with typical operating voltages of a few volts for red LEDs of about 2 volts, for blue LEDs of about 3-4 volts and for UVLEDs of about 4-7 volts. However, substantially all the houses and buildings are wired with 110-120 volt power/50 Hz AC in North America or 208-240 volt/50-60 Hz power sources in most countries around the world. When LEDs are used for ultraviolet purification, biochemical sensing, biomedical instrumentation, and the like, the AC current is converted to low voltage DC. This greatly increases package size or requires additional conversion equipment which increases the cost to the consumer.
A need remains in the art of ultraviolet light emitting diodes for standard high AC voltage (such as 110 volts, 220 volts, etc.) operation.